//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17

// <span>

// constexpr size_type size_bytes() const noexcept;
//
//  Effects: Equivalent to: return size() * sizeof(element_type);

#include <span>
#include <cassert>
#include <string>

#include "test_macros.h"

template <typename Span>
constexpr bool testConstexprSpan(Span sp, std::size_t sz) {
  ASSERT_NOEXCEPT(sp.size_bytes());
  return (std::size_t)sp.size_bytes() == sz * sizeof(typename Span::element_type);
}

template <typename Span>
void testRuntimeSpan(Span sp, std::size_t sz) {
  ASSERT_NOEXCEPT(sp.size_bytes());
  assert((std::size_t)sp.size_bytes() == sz * sizeof(typename Span::element_type));
}

struct A {};
constexpr int iArr1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
int iArr2[]           = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};

int main(int, char**) {
  static_assert(testConstexprSpan(std::span<int>(), 0), "");
  static_assert(testConstexprSpan(std::span<long>(), 0), "");
  static_assert(testConstexprSpan(std::span<double>(), 0), "");
  static_assert(testConstexprSpan(std::span<A>(), 0), "");
  static_assert(testConstexprSpan(std::span<std::string>(), 0), "");

  static_assert(testConstexprSpan(std::span<int, 0>(), 0), "");
  static_assert(testConstexprSpan(std::span<long, 0>(), 0), "");
  static_assert(testConstexprSpan(std::span<double, 0>(), 0), "");
  static_assert(testConstexprSpan(std::span<A, 0>(), 0), "");
  static_assert(testConstexprSpan(std::span<std::string, 0>(), 0), "");

  static_assert(testConstexprSpan(std::span<const int>(iArr1, 1), 1), "");
  static_assert(testConstexprSpan(std::span<const int>(iArr1, 2), 2), "");
  static_assert(testConstexprSpan(std::span<const int>(iArr1, 3), 3), "");
  static_assert(testConstexprSpan(std::span<const int>(iArr1, 4), 4), "");
  static_assert(testConstexprSpan(std::span<const int>(iArr1, 5), 5), "");

  testRuntimeSpan(std::span<int>(), 0);
  testRuntimeSpan(std::span<long>(), 0);
  testRuntimeSpan(std::span<double>(), 0);
  testRuntimeSpan(std::span<A>(), 0);
  testRuntimeSpan(std::span<std::string>(), 0);

  testRuntimeSpan(std::span<int, 0>(), 0);
  testRuntimeSpan(std::span<long, 0>(), 0);
  testRuntimeSpan(std::span<double, 0>(), 0);
  testRuntimeSpan(std::span<A, 0>(), 0);
  testRuntimeSpan(std::span<std::string, 0>(), 0);

  testRuntimeSpan(std::span<int>(iArr2, 1), 1);
  testRuntimeSpan(std::span<int>(iArr2, 2), 2);
  testRuntimeSpan(std::span<int>(iArr2, 3), 3);
  testRuntimeSpan(std::span<int>(iArr2, 4), 4);
  testRuntimeSpan(std::span<int>(iArr2, 5), 5);

  testRuntimeSpan(std::span<int, 1>(iArr2 + 5, 1), 1);
  testRuntimeSpan(std::span<int, 2>(iArr2 + 4, 2), 2);
  testRuntimeSpan(std::span<int, 3>(iArr2 + 3, 3), 3);
  testRuntimeSpan(std::span<int, 4>(iArr2 + 2, 4), 4);
  testRuntimeSpan(std::span<int, 5>(iArr2 + 1, 5), 5);

  std::string s;
  testRuntimeSpan(std::span<std::string>(&s, (std::size_t)0), 0);
  testRuntimeSpan(std::span<std::string>(&s, 1), 1);

  return 0;
}
